Pipes have long been used for the transportation of fluids from one point to another. The distance traveled may be long or short. The system of piping may be simple or complicated. The uses are varied, i.e. air, gas, liquids, steam, etc., and are increasing.
In recent years the use of plastic pipe, e.g. polyvinyl chloride, polypropylene, polybutylene, etc. has grown considerably. The increase is due largely to the advances in technology as to materials and manufacturing of the plastic pipe.
Where metal pipes were utilized, pipe portions were joined by threaded connections or sealed with lead or flexible seals. In the case of plastic pipes, the connections are generally made by applying glue or rubber seals between the portions.
In the use of plastic pipes there are two basic connections for pipes where a leakproof seal is required. First, the two pipes may be permanently fixed together by glue or other suitable means. In this case, the end of the pipe is inserted into a relatively tight fitting bell or coupler with glue applied to the mating surfaces. The end of the pipe which is inserted needs to have a clean, straight cut without sharp edges but not necessarily beveled.
The second connection involves a flexible seal surrounding the pipe and positioned between the two pipes to be connected. A bell or coupler portion of the piping system includes a groove in the inner surface into which a rubber seal ring is placed. An end of pipe is inserted into the bell or coupler and the seal ring. The sizes of the bell, seal ring and pipe are arranged so that the fit is tight but slidable. In this particular connection, it is critical that the end of the pipe be beveled so that the seal ring is not displaced as the connection is started.
Most often in the prior art two separate tools were necessary to accomplish both operations of cutting and beveling a pipe. Further, the cutting of the pipe with prior art devices was often not without undesirable side effects such as distortion of the pipe, uneven or non-perpendicular cuts, etc.
The most frequently utilized method in the prior art for different types and sizes of pipes comprises a number of rollers in a fixed open frame supporting one side of a pipe, with a circular cutting blade radially movable towards and through the other side of the pipe. This type of cutter is unacceptable for most plastic pipe, particularly thin walled plastic pipe, since distortion results through the use of such a tool. A V-shaped block rather than rollers has been utilized to support the pipe from one side. A straight blade may be utilized in place of the circular cutter.
A different approach is taken by combining two or more cutter sections to perform the cutting operation. Each cutter section comprises an open frame with rollers mounted thereon and a straight blade radially positionable between the rollers.
Yet another approach includes a closed frame which surrounds the pipe or tube and is radially adjustable to contact the pipe.
In one such device three radial rollers are used, each of which also have a straight blade cutting means. Spring pressure is applied to each of the rollers and each of the blades which causes holding and cutting of the pipe or tube evenly throughout the circumference. However, self-correction is totally dependent upon operator judgment in setting the spring pressure both on the rollers and the blades.
Another has adjustable slides at opposite sides of an essentially round, closed frame. The slides support rollers which contact a cylindrical surface to be knurled.